X-overs and power...

[HeatSeeker 10+ year member]

Just wondering how is the final ohm load determined in a passive x-over system? Can drivers with different ohm rating be placed in the same x-over system? Also, how is the power distributed? Thanks for any help, I'm kinda new to home audio and trying to build a sound system for my pc (music, games, dvd's)

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[PV Audio 5,000+ posts]

depending on how you wire it ( you'll probably do parallel..much easier and simpler) you can bank on just averaging the impedances. however, there are impedance spikes so you will either want to utilize a strong impedance eq network or you can put in an l-pad. on my most recent project, i used an l-pad with 6 db of attenuation. i'd ask jim about it cause he helped explain it to me.

 

[HeatSeeker 10+ year member]

I have no clue what a lot of that it. Time to get to some reading

 

[thylantyr 10+ year member]

Just wondering how is the final ohm load determined in a passive x-over system?

If you use a 8 ohm (nominal) tweeter, midrange, woofer {etc} in a loudspeaker

design that uses passive crossovers, then as far as you are concerned

{or the amplifier}, the nominal impedance of your speaker can be considered

8 ohms nominal.

Can drivers with different ohm rating be placed in the same x-over system?

yes, but the frequency of the crossover point changes. To keep the same

crossover frequency you have to redo the calculation for your passive crossover

or accept the different frequency if you keep the same crossover parts.

Also, how is the power distributed?

Each driver will draw a certain amount of power, tweeters being least, woofers

being the most power hungry. The crossover can introduce some power loss

as it may be hungry too. /depends

Thanks for any help, I'm kinda new to home audio and trying to build a sound system for my pc (music, games, dvd's)

Generic response: Build some speakers already engineered, there are plenty of

DIY kits or plans on the web.

 

[HeatSeeker 10+ year member]

Each driver will draw a certain amount of power, tweeters being least, woofersbeing the most power hungry. The crossover can introduce some power loss

as it may be hungry too. /depends

.

So is there some sort of formula for figuring out how much goes where? Or is it crossover dependent?

 

[PV Audio 5,000+ posts]

So is there some sort of formula for figuring out how much goes where? Or is it crossover dependent?

think of it like a skinny person sitting around with a bunch of fat people. someone throws in a bucket of KFC. fat people rush in a take up most of the chicken while the skinny person takes a lil, or what is left over. something the weight of a 1" square of wax paper does not need alot of power to drive it. large woofers eat amplifier power and this is also why you have powered subwoofers so that you don't rob the main amp of it's duties. another related topic is the classes of amplifiers. you have classes a, b, ab, d, g, h i believe. a is the most inneficeient (spelling?) b is the most effieicnt, a has best sq, b has worst so people use ab for the benefits of both (i have no energy to go in depth of all of the classes so that'll do for right now). most tube amplifiers use class a technology as they provide the cleanest and unadulturated sound, but at the cost of power. a good rule of thumb for class a amps that i have taken up is that for each watt of output, the amp has already lost 4-5 watts in thermal losses (heat).

 

[HeatSeeker 10+ year member]

Ah okay, thanks for clearing that up. I always wondered how xovers kept the tweet from getting the same power as a woofer and popping. Thanks! //content.invisioncic.com/y282845/emoticons/biggrin.gif.d71a5d36fcbab170f2364c9f2e3946cb.gif

 

[JimJ 5,000+ posts]

you have classes a, b, ab, d, g, h i believe. a is the most inneficeient (spelling?) b is the most effieicnt, a has best sq, b has worst so people use ab for the benefits of both (i have no energy to go in depth of all of the classes so that'll do for right now).

Class C is actually the worst...but it's never used outside of RF applications.

Although that really didn't have anything to do with the original thread topic...//content.invisioncic.com/y282845/emoticons/biggrin.gif.d71a5d36fcbab170f2364c9f2e3946cb.gif

 

[analogkid]

think of it like a skinny person sitting around with a bunch of fat people. someone throws in a bucket of KFC. fat people rush in a take up most of the chicken while the skinny person takes a lil, or what is left over.

hahahahaha that is the most ridiculous comparison ive ever heard...and the funniest!

 

[PV Audio 5,000+ posts]

Class C is actually the worst...but it's never used outside of RF applications.
Although that really didn't have anything to do with the original thread topic...//content.invisioncic.com/y282845/emoticons/biggrin.gif.d71a5d36fcbab170f2364c9f2e3946cb.gif

//content.invisioncic.com/y282845/emoticons/eyebrow.gif.fe2c18d8720fe8c7eaed347b21ea05a5.gif are you testing my gangsta?

- Three Six Mafia